src/components/AppBar/AppBar.tsx

@@ -37,7 +37,7 @@ import { setUserRobotImage } from '../../store/userRobotImage/action'
 import { Container } from '../Container'
 import { ButtonIcon } from '../ButtonIcon'
 
-const metadataController = new MetadataController()
+const metadataController = MetadataController.getInstance()
 
 export const AppBar = () => {
   const navigate = useNavigate()

src/controllers/AuthController.ts

@@ -25,7 +25,7 @@ export class AuthController {
 
   constructor() {
     this.nostrController = NostrController.getInstance()
-    this.metadataController = new MetadataController()
+    this.metadataController = MetadataController.getInstance()
   }
 
   /**

src/controllers/MetadataController.ts

@@ -22,6 +22,7 @@ import {
 import { DEFAULT_LOOK_UP_RELAY_LIST } from '../utils/const'
 
 export class MetadataController extends EventEmitter {
+  private static instance: MetadataController
   private nostrController: NostrController
   private specialMetadataRelay = 'wss://purplepag.es'
   private pendingFetches = new Map<string, Promise<Event | null>>() // Track pending fetches
@@ -31,6 +32,13 @@ export class MetadataController extends EventEmitter {
     this.nostrController = NostrController.getInstance()
   }
 
+  public static getInstance(): MetadataController {
+    if (!MetadataController.instance) {
+      MetadataController.instance = new MetadataController()
+    }
+    return MetadataController.instance
+  }
+
   /**
    * Asynchronously checks for more recent metadata events authored by a specific key.
    * If a more recent metadata event is found, it is handled and returned.
@@ -119,7 +127,6 @@ export class MetadataController extends EventEmitter {
       // Check if the cached metadata is older than one day
       if (isOlderThanOneDay(cachedMetadataEvent.cachedAt)) {
         // If older than one week, find the metadata from relays in background
-
         this.checkForMoreRecentMetadata(hexKey, cachedMetadataEvent.event)
       }
 

src/layouts/Main.tsx

@@ -38,7 +38,7 @@ export const MainLayout = () => {
   const hasSubscribed = useRef(false)
 
   useEffect(() => {
-    const metadataController = new MetadataController()
+    const metadataController = MetadataController.getInstance()
 
     const logout = () => {
       dispatch(

src/pages/nostr/index.tsx

@@ -31,7 +31,7 @@ export const Nostr = () => {
   const navigate = useNavigate()
 
   const authController = new AuthController()
-  const metadataController = new MetadataController()
+  const metadataController = MetadataController.getInstance()
   const nostrController = NostrController.getInstance()
 
   const [isLoading, setIsLoading] = useState(false)

src/pages/profile/index.tsx

@@ -27,7 +27,7 @@ export const ProfilePage = () => {
 
   const { npub } = useParams()
 
-  const metadataController = useMemo(() => new MetadataController(), [])
+  const metadataController = useMemo(() => MetadataController.getInstance(), [])
 
   const [pubkey, setPubkey] = useState<string>()
   const [nostrJoiningBlock, setNostrJoiningBlock] =

src/pages/settings/profile/index.tsx

@@ -12,7 +12,7 @@ import {
   useTheme
 } from '@mui/material'
 import { UnsignedEvent, nip19, kinds, VerifiedEvent, Event } from 'nostr-tools'
-import React, { useEffect, useMemo, useRef, useState } from 'react'
+import React, { useEffect, useRef, useState } from 'react'
 import { Link, useParams } from 'react-router-dom'
 import { toast } from 'react-toastify'
 import { MetadataController, NostrController } from '../../../controllers'
@@ -41,7 +41,7 @@ export const ProfileSettingsPage = () => {
 
   const dispatch: Dispatch = useDispatch()
 
-  const metadataController = useMemo(() => new MetadataController(), [])
+  const metadataController = MetadataController.getInstance()
   const nostrController = NostrController.getInstance()
 
   const [pubkey, setPubkey] = useState<string>()

src/utils/dvm.ts

@@ -13,7 +13,7 @@ import { setRelayInfoAction } from '../store/actions'
 export const getNostrJoiningBlockNumber = async (
   hexKey: string
 ): Promise<NostrJoiningBlock | null> => {
-  const metadataController = new MetadataController()
+  const metadataController = MetadataController.getInstance()
 
   const relaySet = await metadataController.findRelayListMetadata(hexKey)
 

src/utils/nostr.ts

@@ -365,7 +365,7 @@ export const getUsersAppData = async (): Promise<UserAppData | null> => {
   // Check if relayMap is undefined in the Redux store
   if (!relayMap) {
     // If relayMap is not present, fetch relay list metadata
-    const metadataController = new MetadataController()
+    const metadataController = MetadataController.getInstance()
     const relaySet = await metadataController
       .findRelayListMetadata(usersPubkey)
       .catch((err) => {
@@ -835,7 +835,7 @@ const getUserAppDataFromBlossom = async (url: string, privateKey: string) => {
  */
 export const subscribeForSigits = async (pubkey: string) => {
   // Instantiate the MetadataController to retrieve relay list metadata
-  const metadataController = new MetadataController()
+  const metadataController = MetadataController.getInstance()
   const relaySet = await metadataController
     .findRelayListMetadata(pubkey)
     .catch((err) => {
@@ -939,7 +939,7 @@ export const sendNotification = async (receiver: string, meta: Meta) => {
   const wrappedEvent = createWrap(unsignedEvent, receiver)
 
   // Instantiate the MetadataController to retrieve relay list metadata
-  const metadataController = new MetadataController()
+  const metadataController = MetadataController.getInstance()
   const relaySet = await metadataController
     .findRelayListMetadata(receiver)
     .catch((err) => {